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Drake TR7 10R line

Mike Davidsohn G3ZCC All Messages By This Member #84522 Hi everyone. Haven't had much time for the TR7 due to ill health. However I have the transistor for the 10R line. I wondered what caused it to blow in the first place. I checked the 10R line,for resistance to earth with the test leads in both directions. It read 160 ohms. It looked a little low so I pulled,a few boards which used,the l8ne. if/audio, if filter, switch and 2nd mixer. One pulling the second mixer the resistance went to zero. Tried,another board and it was the same. No wanting to blow the transistor does anyone know if that resistance is correct? Thanks Mike G3ZCC ? ? ? ?
Gary Follett All Messages By This Member #84526 开云体育 There is a big disconnect in logic here. How can any 160 ohm resistance drop to zero when you unplug ANY board? Check your work… Gary? W0DVN toggle quoted message Show quoted text On Apr 21, 2025, at 8:18?PM, Mike Davidsohn G3ZCC via groups.io <mike@...> wrote: ? Hi everyone. Haven't had much time for the TR7 due to ill health. However I have the transistor for the 10R line. I wondered what caused it to blow in the first place. I checked the 10R line,for resistance to earth with the test leads in both directions. It read 160 ohms. It looked a little low so I pulled,a few boards which used,the l8ne. if/audio, if filter, switch and 2nd mixer. One pulling the second mixer the resistance went to zero. Tried,another board and it was the same. No wanting to blow the transistor does anyone know if that resistance is correct? Thanks Mike G3ZCC ? ? ? ?
Stan Gammons All Messages By This Member #84533 开云体育 Perhaps Mike meant the resistance went to infinity, not zero?? 73 Stan KM4HQE On 4/21/25 22:39, Gary Follett via groups.io wrote: toggle quoted message Show quoted text There is a big disconnect in logic here. How can any 160 ohm resistance drop to zero when you unplug ANY board? Check your work… Gary? W0DVN On Apr 21, 2025, at 8:18?PM, Mike Davidsohn G3ZCC via groups.io <mike@...> wrote: ? Hi everyone. Haven't had much time for the TR7 due to ill health. However I have the transistor for the 10R line. I wondered what caused it to blow in the first place. I checked the 10R line,for resistance to earth with the test leads in both directions. It read 160 ohms. It looked a little low so I pulled,a few boards which used,the l8ne. if/audio, if filter, switch and 2nd mixer. One pulling the second mixer the resistance went to zero. Tried,another board and it was the same. No wanting to blow the transistor does anyone know if that resistance is correct? Thanks Mike G3ZCC ? ? ? ?
Gary Follett All Messages By This Member #84534 开云体育 Well, that change would not be unexpected when removing a PC board that connects to a given test point… Gary W0DVN toggle quoted message Show quoted text On Apr 22, 2025, at 7:06?PM, Stan Gammons via groups.io <buttercup11421@...> wrote: ? Perhaps Mike meant the resistance went to infinity, not zero?? 73 Stan KM4HQE On 4/21/25 22:39, Gary Follett via groups.io wrote: There is a big disconnect in logic here. How can any 160 ohm resistance drop to zero when you unplug ANY board? Check your work… Gary? W0DVN On Apr 21, 2025, at 8:18?PM, Mike Davidsohn G3ZCC via groups.io <mike@...> wrote: ? Hi everyone. Haven't had much time for the TR7 due to ill health. However I have the transistor for the 10R line. I wondered what caused it to blow in the first place. I checked the 10R line,for resistance to earth with the test leads in both directions. It read 160 ohms. It looked a little low so I pulled,a few boards which used,the l8ne. if/audio, if filter, switch and 2nd mixer. One pulling the second mixer the resistance went to zero. Tried,another board and it was the same. No wanting to blow the transistor does anyone know if that resistance is correct? Thanks Mike G3ZCC ? ? ? ?

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